As a vehicle steering apparatus, an electric power steering device is proposed that assists steering by applying a torque from each of a plurality of electric motors to a steering mechanism via a clutch and a speed reduction mechanism (for example, refer to Patent Document 1).
As an electric power steering device equipped with a plurality of electric motors, there is one in that, for compensating inertia of a certain electric motor, another electric motor is driven.
On the other hand, in a conventional electric power steering device equipped with a single electric motor, inertia of the electric motor is compensated by calculating a compensating electric current and adding the calculated compensating electric current to an electric current that should be supplied to the electric motor.
On the other hand, in an electric power steering device equipped with a plurality of electric motors, inertia of a certain electric motor is compensated mechanically by another electric motor.
As a conventional electric power steering device equipped with a single electric motor, an electric power steering device is conventionally proposed which eliminates torque loss caused by static friction of the electric motor by adding a dither current to an electric current for controlling the electric motor (refer to Patent Document 2).
Further, there is an electric power steering device that is equipped with a single electric motor and eliminates an uncomfortable feeling in steering due to a dead zone by supplying a dither signal to the electric motor when a duty ratio to be applied to a motor driving circuit is not more than a predetermined value (refer to Patent Document 3).